thank you for your query.
The spotting could be anything from your period to implantation
you have to visit your gynecologist and confirm what exactly happened.
A 13 mm egg would not lead to a pregnancy
Only a mature 18 - 20 mm follicle can rupture and ovulate.
Please consult a proper Infertility
Have proper follicular monitoring and documentation of ovulation.
Get your partner's semen analysis
Have your basic hormonal profile done, and status of your fallopian tubes assessed.